Emergency Stop in Engine Room?

[Aaron_2016]

After rereading this thread I'm a bit confused, are we talking a 'crash stop' in terms of going from full ahead to full astern on the engines in the shortest time possible in order to take the way off the ship, or just stopping the engines quickly?

No problem. I'm trying to understand why survivors like Samuel Rule felt the engines suddenly stop and the pounding ceased, and then afterwards he heard the watertight doors close and felt a vibration which made him believe the engines were going full astern. Trying to fathom how it was possible for the engines to stop so suddenly before Murdoch closed the watertight doors.

Here are four theories.

- The emergency telegraphs ring 'stop'.
- The engines crash stop.
- Sam wakes up and feels the engines have suddenly halted.
- The iceberg strikes.
- Murdoch closes the watertight doors.
- Sam hears the bells ringing and a strong vibration as the ice passes underneath the ship and he mistakes that for the engines going full speed astern.


- The emergency telegraphs ring 'stop'.
- The engines crash stop.
- Sam wakes up and feels the engines have suddenly halted.
- The iceberg strikes, but he's so far aft that he doesn't feel it.
- Murdoch closes the watertight doors.
- Sam hears the bells ringing and a strong vibration as the cavitation of the stopped blades or the strong vibration of a lost blade creates the impression the engines are going full speed astern as the liner shakes from 'stem to stern'.


- The emergency telegraphs first ring 'stop' and then 'full astern'.
- The engines crash stop or the reversing gear is pulled.
- Sam wakes up and feels the engines have suddenly halted.
- The iceberg strikes.
- Murdoch closes the watertight doors.
- Sam hears the bells ringing and a strong vibration as the engines start reversing.
- The engines go slow astern as they build up towards full astern, but Captain Smith orders them to stop.


- The emergency telegraphs ring 'stop'.
- The iceberg strikes.
- The engines do not crash stop, but simply come to a gradual stop.
- Murdoch closes the watertight doors but the power has gone out in the boiler rooms near Sam and the bell does not ring.
- Sam wakes up and notices the ship has stopped. The power comes back on in the boiler rooms and the bells start ringing in some of the rooms with a delayed effect.
- The engines are going slow astern or slow ahead at this time and Sam mistakes that for full speed astern.


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[Jim Currie]

A trip over to YouTube to search "Kempton Park steam engine" is recommended. Though the engine is working pumps and not propellers it is the closest thing to an Olympic class steam engine we'll ever see. The video I watched shows start up and a nice walk around the engine showing the various gauges. The engine is turning about 15-20 rpm from what I recall. Try to imagine that massive engine doing 70rpm and then instantly having the reversing gear thrown over to astern. I'm no marine engineer, just a humble diesel mechanic and hobby machinist, but the thought of instantly reversing any engine (especially a massive steam engine) just sets off all sorts of warning bells and red flags in my head. From what I know about steam engines (self-taught and not an expert) my gut feeling is that the process shown in JC's movie would be pretty much how it would have looked.

Again, I'm not an expert. This is just my opinion regarding any possible full ahead to full astern order.

Hello Tim.

There was a coal trimmer named Dillon stationed in the main engine room during nthe emergency sequence. Here is his evidence. It gives you an idea of timing:

715. Did you feel the shock when the ship struck? A: - Slightly.
3716. And shortly before that had the telegraph rung? A: - Yes.
3717. Can you say at all how long before she struck that was?
A: - Two seconds.
3718. What was the order given by the telegraph? A: - I could not tell you.
3719. You just heard it ring. Then a few seconds after that you felt a slight shock?
- Yes.
3720. Was anything done to the engines? Did they stop or did they go on? A: - They stopped.
3721. Was that immediately after you felt the shock or some little time after? A: - About a minute and a half.
3722. Did they continue stopped or did they go on again after that?
A: They went slow astern.
3723. How long were they stopped for before they began to go slow astern? A: - About half a minute.
3724. For how long did they go slow astern? A: - About two minutes.
3725. Two or three did you say? A: - Two minutes.
3726. And then did they stop again? A: - Yes.
3727. And did they go on again after that? A:- They went ahead again.
3728. For how long? A: - For about two minutes.
3729. Then did they stop the boat after that? A: - Yes.

 

[Julian Atkins]

I have stopped and reversed many miniature steam locomotives by pulling the reverser lever over from forward to 'backgear' with the regulator opened. It is quite fun to do! This has been on portable 'up and down' tracks as opposed to a continuous track that comprises a circuit. Never any mechanical problems as a result. In fullsize you would close the regulator momentarily whilst doing this on a steam locomotive with lever reverse.

Titanic was a bit more complicated as it also had the turbine, and effects on the condenser, but I have not the slightest doubt that the massive machinery of the compound steam engines would have suffered no damage in a sudden stop, then immediate reverse into backgear. The strain would have been taken by the prop shafts and their massive thrust bearings and the propellors.

Cheers,

Julian

 

[coal eater]

engine itself cant be damaged from going full ahead to full astern.but strain to material can eventually lead to some malfunction,i think one of british or american WW2 aircraft carriers had once gone from full ahead to full astern and something wrong went here so propeller shaft flexed and demolished few decks.
was it british hms illustrous?

crash stop on titanic technically was possible,but never was done at all. we all know the metalurgy in 1900 years was not best so crash stop probably would be not healthy for engine peripherials.

 

[Julian Atkins]

Hi 'coal eater',

I don't know about Harland and Wolff, but by 1905 most major UK railway companies that built steam locomotives had established scientific metallurgy testing labs.

now take crash stop on titanic,titanic stops engine in one second and what would happen? crankshaft would be grinded and destroyed possibly piston rods would flex and jam the pistons in cylinders for good.

There is no way the crankshaft of the compound reciprocating steam engines on Titanic could be damaged. They were massively built with bearings between each crank and at each end. The idea that a piston rod would flex and jam the pistons is just silly. The piston rod is very accurately guided by the crosshead in the slidebars. The piston rod cannot do anything but go up and down perfectly guided.

Cheers,

Julian

 

[Aaron_2016]

There is no way the crankshaft of the compound reciprocating steam engines on Titanic could be damaged. They were massively built with bearings between each crank and at each end. The idea that a piston rod would flex and jam the pistons is just silly. The piston rod is very accurately guided by the crosshead in the slidebars. The piston rod cannot do anything but go up and down perfectly guided.

Cheers,

Julian

Glancing through the newspapers I discovered that defects were found in the Olympic's crankshaft in 1932. Not sure if they were caused by age, or if the liner was put through too much stress e.g an emergency stop. Here are news reports (with emphasis on the damage).


OLYMPIC SAILING CANCELLED
Passengers Offered Accommodation on the Georgic. The White Star Line announced yesterday afternoon that the usual examination of the engine room of the Olympic, after she arrived at Southampton from New York on Friday last, revealed that a small fracture was discovered......

OLYMPIC’S TROUBLE
Owing to an engine defect the sailing of the White Star liner Olympic from Southampton to New York today was cancelled. A small fracture has developed in one of the journals of a crankshaft. It will be repaired in time for her next voyage.....

OLYMPIC'S DEFECTS CONFERENCE WITH SHIPBUILDERS
The White Star Line has issued the following statement regarding the liner Olympic, at present docked in Southampton: There will be a conference on Tuesday at the head offices of the White Star Line......

THE OLYMPIC’S ENGINE TROUBLE
The conference lasted several hours, and at its close the following statement was issued;— “The White Star Line announces the Royal Mail steamship Olympic is to undergo a complete overhaul".....

OLYMPIC TO UNDERGO THREE MONTH OVERHAUL
An order has been placed with Messrs Harland and Wolff for a new propeller shaft for the White Star liner Olympic which is to undergo three months overhaul.....


The following year the Olympic continued to have problems with her engines.


LINER 12 HOURS LATE - OLYMPIC DEVELOPS ENGINE TROUBLE
The White Star liner Olympic reached Plymouth today from New York, 12 hours late owing to engine trouble. Three days ago a defect in a turbine put one of her three propellers out of action and reduced her speed....

OLYMPIC TWELVE HOURS LATE - TROUBLE IN TURBINE
The White Star liner Olympic reached Plymouth yesterday from New York twelve hours late owing to engine trouble.



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[David G. Brown]

Metal has lots of properties and fails in many ways. Single events like "crashing back" to avoid an iceberg are less...far less...damaging than the vibrations of everyday operation. There's another kind of vibration built into every engine. This comes from the pulses of power pushing on the piston heads. It's a real killer of modern gasoline engines. And, as if that were not enough, the moving mass of the engine itself would put oscillating loads on the crank bearings, bearing stands, and bed plate of a steam engine.

While Titanic's mains were smooth running and well balanced, every revolution of the crank produced three "pulses" or vibrations from water being compressed between the hull and tip of each blade. At 72 rpms on the engines that's a vibration frequency of 716 cycles per minute. Over the course of a single one-way trip the drive train and engines that more than 6-million vibrations. It is axiomatic in the world of metalworking that vibrations cause metal fatigue. Multiply this by the number of trips Olympic made over the nearly quarter century between being placed in service and discovery of journal cracks and things look quite different. The engines in Titanic's sister seem to have been rather exceedingly well built.

Would anyone out there expect their automobile, washing machine, or other such devices to have a 25 year mean time between failures? Olympic did just that and was still able to be repaired and continue functioning.

-- David G. Brown

 

[coal eater]

in normal conditions ship engines will never fail,all depends how much they are being used and how often they are inspected. crash stop would be more dangerous to passengers and crew thought.

 

[Daniel A. Soto]

Now I may be mistaken, but I thought the Olympic class engines didn't have a reversing lever the way it is show in James Cameron's movie.

 

[Rancor]

Here is a model of one of the engines created by Stevefury with the various controls labelled.

I believe the Fwd/Trim/Rev lever is the reversing control, but you are correct it isn't the massive arm that requires a person to throw their entire body weight on it to move like in the movie.

 

[Daniel A. Soto]

Thank you, Rancor!